A projector which is a projection-type display apparatus displays an image by modulating light incident from a light source and enlarging and projecting the modulated light on a screen. As the projector, there is a projector including an optical panel such as a liquid crystal panel which functions as a light valve. At such a projector, light with relatively high intensity is made incident on the optical panel to enlarge and project an image on the screen. Therefore, a temperature of the optical panel is likely to increase by radiation of light, and there is a possibility that image quality may degrade due to thermal strain such as thermal expansion in association with such increase in the temperature.
Therefore, Patent Literature 1 discloses a projector which cools a liquid crystal panel using a coolant. Such a projector includes inside an optical element holding portion having a flow channel, inside of which the coolant flows, to hold the liquid crystal panel, a liquid pumping unit which sucks and pumps the coolant, a supply tank, inside of which the coolant is retained, a radiator which receives heat of the liquid crystal panel, and a tubular member connected so that the coolant circulates through the optical element holding portion, the liquid pumping unit, the supply tank and the radiator.